Method of treating cellulose textile material and the treated material



United States Patent METHOD OF TREATING CELLULOSE TEXTILE MATERIAL AND THE TREATED MATERIAL William Julius van Loo, In, Midrliesex, and Samuel James OBrien, Dunellen, N.J., assignors to American Cyanamid Company, Stamford, Conn., a corporation of Maine No Drawing. Continuation of application Ser. No. 796,209, Mar. 2, 1959. This application June 6, 1962, Ser. No. 200,315

Claims. (Cl. 117-1394) The present invention relates to the method of applying thermosetting cyclic urea-formaldehyde resins to cellulose-containing textile materials, and to the materials so treated, and more particularly to a method for obtaining higher than normal tensile strength on cellulose-containing textile materials with little or no sacrifice in wrinkle recovery.

In the past, the textile industry has employed many finishes of the resin type to impart wrinkle resistance and dimensional stability to cellulosic materials, such as cotton, viscose rayon and the like. One of the first of these resins to be used was the urea-formaldehyde type. This product had serious defects in that it caused extensive tensile strength losses when the amount of resin applied was snificient to give satisfactory crease resistance. This was particularly true when used on cotton fabrics. In addition, the loss in tensile strength when a fabric was scorched after chlorine bleaching was extensive.

Gradually, the urea-formaldehyde resin was replaced with the methylated methylol melamine resins, which imparted satisfactory crease resistance to cellulose textile materials at lower concentrations and without serious loss in tensile strength due to chlorine belaching. However, during use, it was discovered that certain methylated methylol melamines had the somewhat serious defect of discoloring when the fabrics were subjected to a bleaching operation in which chlorine was used.

In order to avoid the disadvantages of yellowing following chlorine bleaching which resulted when some methylated methylol melamine resins were used, recourse was had to the use of ethylene urea type resins. These materials had the advantage that they did not discolor fabric treated therewith after bleaching with chlorine and further that they could be used in high concentrations to obtain excellent high wrinkle recovery without imparting stiffness to the fabrics. The ethylene urea or cyclic urea type resin, however, had the disadvantage that they gave a substantially greater loss in tensile strength than Accordingly,,it is an object of the present invention to provide a process whereby a wrinkle resistance of high order may be achieved, while simultaneously maintaining a high order of tensile strength.

It is a further object of the present invention to provide such a process which maybe readily and economically adapted by most textile finishing installations.

These and other objects and advantages of the present invention will become more apparent from the detailed description thereof set forth hereinbelow.

ice

In accordance with the present invention a method is provided for the treating of cellulose-containing textile materials whereby a high order of tensile strength and wrinkle recovery are obtained even at high resin solids on the fabric, which comprises applying thereto a formaldehyde condensate of a cyclic urea, and thereafter curing said cyclic urea in the presence of a zinc salt catalyst in an atmosphere of steam. Following the effective curing of the above described conditions, the so finished fabric is allowed to dry, either at room temperature or under the normal drying conditions employed in textile finishing plants.

By the expression formaldehyde condensates of cyclic ureas, as that term is employed herein, we refer to the methylol derivatives, of ethylene urea and certain of its homologs, as for example, 1,2-propylene urea, and certain alkyl substituted derivatives thereof, as well as hydroxyl substituted derivatives thereof.

In general, these compounds may be characterized by the following general formula:

wherein R through R, are selected from the group consisting of hydrogen, saturated aliphatic alkyl groups containing from 1 to 4 carbon atoms, and hydroxyl. The preferred species within the above general formula is where R through R is hydrogen or where one of the values is methyl and the remainder are hydrogen. With respect to alkyl substitution for R through R the total number of carbon atoms in substituting groups should not exceed 6.

While in the above general formula, the dimethylol derivative is illustrated, it should be noted that while the dimethylol derivative is preferred, cyclic ureas having at least 1.5 mole of combined formaldehyde as methylol formaldehyde are fully contemplated in accordance with the present invention.

I The cyclic ureas which are condensed with formaldehyde to form methylol derivatives employable in the process of the present invention may be prepared in accordance with'known prior art procedures by reacting a suitable diamine, including the substituted diamines, with urea, as for example, in accordance with the procedures described in US. Patents Nos. 2,436,311 and 2,517,750, which are incorporated herein by reference. As examples of suitable S-mernbered cyclic ureas within the purview of the present invention, the following are illustrative: Z-imidazolidinone (ethylene urea); .3-methyl-2-imidazolidinone, 1-2-propylene urea; 3,4-dirnethyl-2-imidazolidinone; 3,3,4-trimethyl-2 imidazolidinone; 3,3,4,4-tetramethyl-Z-imidazolidinone; 3,4-diethyI-Z-imidazolidinone; 3,3-dimethyl-4-ethyl-2-imidazolidinone; 3-methyl-3-ethyl-2-imidazolidinone; '3,4-dimethyl-3-n-propyl 2-imidazolidinone; 3-isopropyl-2-imidazolidinone;' 3methyl-3-isopropyl-4-ethyl-2-imidazolidinone; 3-n butyl-2-irnidazolidinone; 3-ethyl-4-sec-butyI-Z-imidazolidinone; 3-hydroxy-2-imidazolidinone; 3,4-dihydroxy-Z-imidazolidinone; 3-hydroxy-4-methyl-2-imidazolidinone; 3,4-dihydroxy-3,4-dirnethyl-Z-imidazolidinone; 3-hydroxy-3-methyl-4-n-propyl-2-imidazolidinone; and 3-hydr0xy-3-ethyl-4-methyl-4-isopropyLZ-imidazolidinone.

from one to three moles of the formaldehyde and pref-.

erably with from betweentwo to three moles of formaldehyde. The methylolation may be carried out at a pH of inaccordance with the present procedure and more preffrom between 3 and and preferably at a pH of from between 7 and 10 at a temperature of from between '40 and reflux or about 100 C. until solution is achieved. Thereafter, the reaction mixture is cooled. Preferably, the mole ratio between the cyclic urea and formaldehyde is 1 to 2, respectively. When the formaldehyde is increased, thedegree of methylolation is not appreciably I increased and the presence of increased amounts of free formaldehyde increases handling difiiculties and presents other known problems. When the mole ratio is 1 to 2,.

the resulting product may be identified as a dimethylol compound in that by analysis, as much. as 1.9 moles of the available 2 moles of formaldehyde. are combined.

As indicated hereinabove, the present invention-is ap plicable .to textile materials containing cellulose. The term cellulose textile material and similar expressions, as they are employed herein, is intended to include textile materials including fibers, filaments, yarns, formed fabrics, containing at least 50% cellulose. Materials,'as for example, flax, cotton, jute, hemp, sisal, and regenerated cellulose, as for example, viscose rayon, cuprammonium or the like are alsoincluded; In its more preferred sense, expressions-such as are identified above and similar ex pressions, are intended to include cotton and viscose rayon textile fabrics, whether they be woven, knitted, non-woven,

felted or otherwise formed. V The methylol condensates of cyclic ureas as they. are

identified hereinabove may be applied to textile materials in amountsvarying betweenl to 40%, based on the dry weight of the material, and preferably-in amounts of from between 2.5 and by weight. These heat-curable resinous materials may be applied by padding, dipping, spraying, immersion or other suitable techniques,

but are preferablyapplied by conventional padding proc- I esses, as in the case of formed fabrics, in that most textile finishing installations areequipped for such-applications.

It is a unique characteristic of the present process that the ureas in accordance with this invention and the unexpected results obtained therefrom are only'realized when the: resinis cured in the presence ofzinc salts as curing accelerators or catalysts. Thus, for example, mostfof the better known curing accelerators presently employed in 'alkanol amine salts, such as triethanolamine hydrochloride, and free acids, such as oxalic,.tartaric, and the like,

are not applicable irraccordance with thepresent process. As noted, the only catalysts that we have found to be suitable in accordance with our present invention are in-. organic salts of zinc. fZinc salts as that term is employed herein, is intended to include the salts derived from the reaction of zinc oxide or zinc hydroxide with inorganic acids. Thus, for example, the expression includes-zinc chloride, zinc sulfate, zinenitrate, and the like. Of these V enumerated, zinc nitrate is greatly preferred because .of its solubility and pad bath stability.

In general, zinc catalysts are employed in amountsof from between -1 and 36%, based on the weight of resin solids employed erably in amounts of from between5 and 15%, based on the weight of resin solids employed in a given treating solution.

In addition to the present invention beinglimited to cyclic urea resins and zinc salt curing accelerators in order to achieve unexpected properties, it isessential that Q curing be accomplished in anatmosphere of steam so that in'eifectthe cure is accomplished'when' thefinished material is in the wet state. Althoughan atmosphere of steam atmosphere below about .212 F. is readily accom:

plished by curing at sub-atmospheric pressures. -In general, longer time cycles are required at the lower temperatures. and shorter cycles for the higher. temperatures. Although curing in an atmosphere of steam is "greatly preferred, the curing may be'accomplished in the absence of added steam and only that steam which is generated through the drying of the impregnated, fabric need be employed. Normally, this may be accomplished by placing the treated material prior to cure in a substantially' (almost completely) closed container or chamber. Additionally, a partially saturated atmosphere of steam may. be employed. A confined or unconfined atmosphere may be used. i i

' Ingeneral, curing time's employed in the present process are somewhat longer than those conventionally used.

Thus, in general, times from about 15 minutesto about 3 hours are employed to bestadvantages. While the time of cure may be shortened or. lengthened within given limits depending :uponv other variablesssuch as steam temperature, amount of vcatalysts, etc., it is usually preferred to effect cure at times between about 30 minutes and 2 /2 hours.

In order to illustrate the present-invention, the following examples are given by way of illustration. No details or enumerations contained therein should be construed as limitations onthe present invention, except insofar as they appear in the appendedclaims. All parts and percentages are by. weightunless otherwise indicated.

EXAMPLE 1 Pad 'baths were prepared containing 19.0%, 27.5% and 35.0% resin solids of dimethylol ethylene urea and 12% on the weight of the resin solids in ther bath of zinc nitrate or magnesium'chloride as curing accelerators.

l6.l%,. 23f.4%' and 29.6% applications of dimethylol ethylene urea were made on x 80. cotton .percale by padding with the above solutions,'using a pick-up of Y 'Two'methods of curing were used:

A. Dried at 225 F. for 2 minutes and then heated at 350 F. for 1.5 minutes by the standard procedure.

B. The wet fabric was rolled and placed in ,a test tube having a small vent forescape of pressure; 1 The test tube- Wrinkle Recovery Tester following the tentativeTest 1 Method 66-1956 described on page 158 of the 1957Technical; Manualand. .Year Bookv of the American Association of Textile Chemists and Coloristsj vol; 33. ,Thetensilestrength was measured .on a Scott Tester according to A.S.T.M.; standards and the values reported are in. pounds; 3 i

5 The results of these applications are shown in Table I below.

ther illustrates the unique character of zinc salts in the. present invention. Compare with Example 1.

Table 1 Percent Percent Nitrogen Tensile Wrinkle Resin on Catalyst Curing Strength, Recovery Fabric Conditions Pounds Total Orig. Washes 16.1 Zl1(NO3)2- 2. 7 2. 2 52 299 16.1. Zn(NOa)2 2. 5 1.7 74 285 23.4. Zn(Na)a A 3. 7 2. 4 57 311 23.4 Zn(NOa)2- 3. 5 2.2 73 293 23.4. MgOlo 3. 3 2. 6 52 291 23.4 MgClg 3.1 0. 6 94 223 29.6 ZIl(NO3)z 4. 2 2. 6 56 297 29.6 Zn(N,O )g 4.9 2.5 77 285 29.6- MgOlv A" 4.0 2. 6 52 295 29.6- MgOlq B 3. 7 0.6 94 226 The following conclusions may be drawn from these results:

(1) Dimethylol ethylene urea can be cured on the fabric at 210 F. (in steam) with zinc nitrate as a catalyst to obtain approximately normal wrinkle recovery and higher than normal tensile strength. Good fixation of resin is obtained, as indicated by the nitrogen analysis.

(2) Curing under the same conditions with magnesium chloride as the catalyst gives poor fixation of the resin and lower than normal wrinkle recovery. In addition, Table I hereinabove clearly illustrates the merit of the present invention, in that as will be 'seen the conditions of the present process result in wrinkle recoveries substantially as good as are those obtained under normal curing conditions, but with tensile strengths of the order of at least about 70 pounds, which is considerably higher than that normally obtained when wrinkle recovery values of this magnitude are obtained. This tensile strength is of the order of 20 pounds higher than normally obtained for Wrinkle recoveries of this magnitude. In general, it has been found that tensile strength values of the order of at least 80 pounds may be achieved for wrinkle recoveries of 240 and higher, and that for wrinkle recoveries higher than 280 tensile strengths of the order of greater than about 70 pounds are readily achieved by employment of the present process. Such values heretofore have not been possible.

EXAMPLE 2 In separate applications, 17.65% of dimethylol ethylene urea was applied to cotton percale employing varying amounts of well known curing accelerators, based on the weight of resin solids. An 85% wet pick-up was obtained, leaving resin solids on the weight of the fabric. The fabric was then steam cured for 2.5 hours at i 210 F. The applied solutions were as follows.

The results of the applications according to Example 2 are set forth in Table II below.

Table 11 Treatment: Wrinkle recovery (total W-l-F A 175 Untreated 150 No tensile strength determinations were made since they were not warranted in view of the wrinkle recovery obtamed employing these known catalysts. Table II fur- EXAMPLE 3 In separate applications, solutions containing 9.4, 13.5 and 17.65 solids of dimethylol melamine and of dimethylol ether of trimethylol melamine were applied to cotton percale. The solutions contained 1 2% of either mag- 'nesium chloride or zinc nitrate based on the weight of resin solids as catalyst. An wet pick-up was obtained in all cases, leaving the solids content indicated in Table III below on the fabric. The cures identified as A and B in said table are the same as those described in Example 1 hereinabove.

tained. Table IV illustrates the unique character of the cyclic ureas in the present invention. Compare Examples 1 and 3.

' EXAMPLE 4 In separate applications, solutions containing 24.9 and 32.5% (solids basis) of the dimethyl ether of dimethylol urea (UF) was applied to cotton percale employing 12%, based on resin solids, of either magnesium chloride or zinc nitrate as catalyst. An 85% wet pick-up was obtained and the finished fabric cured by the cures identified as A and B in Examples 1 and 2 above. The results are recorded in Table IV below.

Table IV MgOh (N a)2 UF Solids Cure A Cure B Cure A Cure B WR TS WR TS WR TS WR Ts 35:33:32: 3Z3 3:: iii :1: 53% 22 it? it In Table IV above, tensile strength determinations for fabrics having a urea-formaldehyde resin thereon cured with magnesium chloride were deemed unwarranted, since the wrinkle recovery obtained by steam cure was not satisfactory. While good wrinkle recovery can be obtained employing urea-formaldehyde resins by steam cur- '3' ing where a zinc salt is the catalyst, no significant advantage in tensile strength is obtained with respect to those achieved by conventional cure. The present table further demonstrates that the advantages of the present invention are for the most part limited to cyclic ureas "of the type contemplated by the present invention.

While the present invention has been described specifically with respect to the methylol condensates of ring membered cyclic ureas, it isto be understood that the term as it isemployed hereinabove is intended to include their alkylated and in particular their methylated derivatives. Sir1ce alkylationiand particularly methylation are, in general, employed to stabilize aminoplast resins, alkylations of the condensates contemplated in accordance with the present; invention are in general 7 unnecessary, in that thesematerials are themselves sufiiciently stable.

However, should alkylation or methylation be desired, this may be carried out in accordance with the prior art procedures known for the methylation' of aminoplast resins.

Any of the cyclic ureas identified hereinabove or catalysts set forth therein suitable for use in the presentinvention maybe employed singly or in combination with one another, and to some extent with other known teX-' tile finishing resins, as for example, urea-formaldehyde resins and their alkylated derivatives, melamine-formaldehyde resins and their alkylated derivatives, 6-ring memberedcyclic ureas, such as 1,3-propylene urea-formaldehyde, condensates and derivatives thereof, epoxy resins,

such as thediglycidyl ether of ethylene glycol, diglycidyl ether per se and the like guanamine-formaldehyde resins and their alkylated derivatives, acetone-formaldehyde resins and other knowntextile finishing resins wherein their incorporation with the cyclic ureas in accordance with the present invention does not significantly affect the properties sought to be achieved. 7

In addition, it will be apparent that other textile fin-.

ishing assistants may be employed in the. processof the present invention, such as wetting agents, softeners and the like, insofar as their inclusion in the treating bath on the weight of resin solids, v V

4. A method according to claimxl wherein the catalyst is zinc nitrate. V I

5. A process according to: claim-'hwherein the cyclic urea is ethylene urea.

6. A process according to claim v 1, wherein the cyclic urea is 1,2-propylene urea.

7. A'process according to claim 1',x wherein-the curing takes place at a temperature of from between qabout 80 F. to about250 F.

8. A cellulose containingmaterial prepared: by the process of claim 1 having from 1 to 140% based on the'weight of the textile material, of a water-soluble cured formaldehyde condensate of a S-membered cyclic urea thereon and characterized by .high tensile strength and Wrinkle recovery.

9. A cotton textile material prepared by the process of claim 1 having from 1 to 40% based ontheweight of V the textile material ofa cured formaldehyde condensate.

of ethylene urea thereon;

10. A method for treating formed cotton fabric whereby high tensile strength andwrinkle recovery are obtained, which-comprises applying from" an aqueous solution from about 2.5 to about 25% of a formaldehyde condensate. of a S-membered cyclic ureaand a zinc salt of an inorganic acid as a catalyst therefor, said zinc salt being selected from the group consisting of zinc" chloride,

zinc sulfate and zinc nitrate, and'immediately, without intermed1ate drying, wet curing said cyclic urea in the presenceof said zinc salt catalyst in an atmosphere of wet invno way significantly impairs the effect sought to be achieved.

This applicationis a continuation application of application 'Serial No. 796,209, abandoned.

. We. claim:

1. A method of treating cellulose textile material wherefiled March 2, 1959, now

by high tensile strength and wrinkle recovery are ob-- tained, which comprises applying thereto,from anaqueoussolution, a formaldehyde condensate of a S-membered cyclic urea and a zinc saltof an inorganic acidas a catalyst therefor, and immediately, without'intermediate drying, wet curing said cyclic urea in an atmosphere of steam and thereafter drying the so-processed cotton fabric.

' References Cited by-the Examiner UNITED STATES. PATENTS 2,088,227 7/37 Battye etval'." .117 "139.4

2,254,001 8/41 Conway. 2,661,312 12/53 Richardson 117-1394 2,763,574 9/5 Ruperti 117-138.5 2,899,263: 8/59 Nuessle et a1. 117' -139.4 XR 2,917,412 12/59 Reinhardtetial. 117-"-139.4 2,974,065 4/61 WILLIAM D. MARTIN, Primary Examiner. V RICHARD D. NEVIU SQExaminerH Mann er al. 117-145 XR 1 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,177,093 April 6, 1965 William Julius van Loo, Jr. et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected 'below.

Column 1, line 34, for "belaching" read bleaching column 2, line 15, strike out the comma; column 3, line 10, for "ureas" read urea line 34, for "cuprammonium" read cupramonium rayon column 4, line 38, for "catalysts" read catalyst column 7, line 31, after "like" insert a comma Signed and sealed this 5th day of October 1965,

%(SEAL) lAuest:

iERNEST W. SWIDER EDWARD J: BRENNER Attesting Officer 7 Commissioner of Patents 

1. A METHOD OF TREATING CELLULOSE TEXTILE MATERIAL WHEREBY HIGH TENSILE STRENGTH AND WRINGLE RECOVERY ARE OBTAINED, WHICH COMPRISES APPLYING THERETO, FROM AN AQUEOUS SOLUTION, A FORMALDEHYDE CONDENSATE OF A 5-MEMBERED CYCLIC UREA AND A ZINC SALT OF AN INORGANIC ACID AS A CATALYST THEREFOR, AND IMMEDIATELY, WITHOUT INTERMEDIATE DRYING, WET CURING SAID CYCLIC UREA IN AN ATMOSPHERE OF WET STEAM MAINTAINING THE TEXTILE MATERIAL IN THE WET STATE UNTIL COMPLETION OF THE CURE AND THEREAFTER DRYING THE FABRIC. 